Khlong Saeng Before Cheow Lan Lake
KHLONG SAENG · HISTORY
Khlong Saeng Before Cheow Lan Lake
Khlong Saeng Wildlife Sanctuary was protected in 1974, more than a decade before the Cheow Lan reservoir was created. The hydroelectric project later flooded lowland valleys and fragmented parts of the former continuous forest, fundamentally changing the landscape visible today.
Cheow Lan Lake transformed former forest valleys into a reservoir landscape of waterways, shorelines and isolated forest fragments.
1974 — Wildlife Sanctuary Established
A Royal Decree designated Khlong Saeng as a wildlife sanctuary in 1974. The original protected area was recorded as 772,500 rai and covered forest in what is now Surat Thani Province.
1980s — Land Withdrawn for the Hydroelectric Project
Conservation records summarising the legal changes report three withdrawals: 49,875 rai in 1983, 31 rai in 1985 and 526 rai in 1986, a combined 50,472 rai associated with the dam and hydroelectric development. The resulting sanctuary area is reported as 722,068 rai.
1987 — A Reservoir Replaces Forested Valleys
Scientific literature describes the Chiew Larn reservoir as having been created in 1987 in the forested interior between Khao Sok National Park and Khlong Saeng Wildlife Sanctuary. Research on the new reservoir recorded the ecological consequences of isolating forest on former hilltops and ridges.
The Islands Became a Natural Experiment
Researchers studied small mammals on land-bridge islands formed by inundation. Within only several years, island communities had already changed in composition and abundance. A later conservation review reported near-complete local extinction of the studied small-mammal fauna on reservoir islands over approximately 25 years after fragmentation.
What Visitors See Today
The dramatic scenery is therefore also an ecological history. Forested islands are fragments of a formerly connected landscape; long inlets occupy flooded drainage systems; and intact forest beyond the shoreline remains essential for species that require large, connected habitat.
Why This History Belongs in a Travel Guide
Understanding the landscape makes a boat journey more meaningful. Cheow Lan is beautiful, but its beauty has a complex history. Responsible interpretation can celebrate the scenery while acknowledging the conservation lessons produced by the reservoir.
KEY FACTS
GOOD TO KNOW
1974: sanctuary established | 1983, 1985, 1986: documented land withdrawals | 1987: reservoir described in scientific literature as created | Ecological legacy: habitat fragmentation and long-term wildlife research
Dates in popular sources can vary between dam construction, completion, impoundment and reservoir formation. This guide uses dates as stated in the cited legal and scientific sources.
Frequently Asked Questions
Was Khlong Saeng protected before the dam?
Yes. Khlong Saeng was designated as a wildlife sanctuary in 1974, before the Cheow Lan reservoir was formed.
Were parts of the sanctuary removed for the dam?
Yes. Conservation records summarising Royal Decrees report three withdrawals totalling 50,472 rai connected with the hydroelectric development.
Why are there so many islands in Cheow Lan Lake?
Many are former hilltops and ridges that remained above water after valleys were inundated by the reservoir.
Did reservoir creation affect wildlife?
Yes. Multiple scientific studies have documented changes associated with habitat loss and fragmentation, including major changes in small-mammal communities on reservoir islands.
Is the reservoir still scientifically important?
Yes. The wider Khlong Saeng–Khao Sok landscape continues to support research on threatened mammals, birds and conservation ecology.